1. Field of the Invention:
This invention relates to an earth auger, and more paticularly, to an earth auger which can be used for excavating a general water well or the like in addition to boring for an anchor engineering method and a grout pouring hole.
2. Description of the Prior Art:
The earth auger conventionally used has a screw having an upper end coupled with a swivel reduction gear in which a vertical type motor is incorporated to rotate the screw and bore while lowering the screw along a leader.
On the other hand, a boring machine rotates a drill extending through a swivel head rotated by a bevel gear to bore while giving a feed to the drill.
Since the earth auger bores with the screw, it has a small excavating reaction compared with the boring machine. On the other hand, since it is provided on the upper end with a drive source, it needs a leader for guiding the screw and resules in a large size as a whole. Also, since the screw is fed by its own weight, it is difficult to change the feed speed according to soil quality.
Since the boring machine has a large weight standing the excavating reaction, it is not easy to transport and not a convenient one.